Problem with Forums

I enabled forums in the modules list, and then created one category and added terms to it. After adding it I created some forum topics under those categories, these forum topics are displayed when i click <> link available at the end of the forum topics block available in the left hand side of my site.
Now I am able to view the forum that i have created.

I created another category and added forum topics under it but i am not able to view them now. I am able to view only one category relaetd forums at a time. What should I do to solve this problem?

Thanks in advance for your help.